Dang that is very interesting. Is it just that everybody is trying to out-game everyone else, so when one guy picks up on something and it is working, soon enough others will pick up on it and arbitrage (maybe not the right word, but you get my drift) away any excess profit, and maybe take advantage of knowing the first guy's thinking, in essence taking his lunch money? Is it as simple as its a dog-eat-dog world out there, and you need to be constantly evolving, even moreso these days?
A few things...
1. The principle of "Keep doing what has worked and the market will eventually knock you on your ass". (Applies more to "theme" players than traders) IOW... "getting it right" is a "right now" kind of thing. We tend to think of star players in the "now" as truly star players... the ones who are smarter and will keep knocking it out of the park in the future. For the most part, that's wrong. Lots of examples.
2. The market changes. (See point #1) As a trader/investor, YOU have to be aware of change and adapt.
3. Lesson... "Keep trying to get it. When you do, make something of it. Always trade with stops. If you're going through a period when you're not doing as well as you like, keep as much of your capital intact as you can (stops) for the next time you get it right".
4. 80/20. Just as most traders' gains come from 20% of their trades, most players' CARRERS show the same 80/20. That is, your best years... 20% of all of your years.... will hold the lion's share of your career gains. It's worth a lot over time if the "80% not my best years" are somewhere between small losses and modest gains.... or better, if you can muster it.